The present invention relates to communication systems and services for distributing digital content, and more particularly, to techniques for properly associating subscribers with appropriate policy servers regardless of the physical location of the subscriber.
FIG. 1 shows a prior art system 10 for delivering digital content to a number of subscribers. An application function 12 (in this example a P-CSCF; proxy call session control function), provides session setup functions to enable subscribers to make VoIP calls, or can also be a server, which serves digital content such as a video stream to one of several subscribers 14. The subscribers may include any of a number of electronic devices such as telephones or personal computers. These electronic devices may be wireless or they may be connected to a local wired network.
During a session, the digital content the application server 12 provides to a subscriber 14 may pass through a number of network components. The content passes through enforcement points(s), but the signaling to request policy is signaled between the policy elements in the diagram—the policy router 16 and the policy server 18 as well as the enforcement point.
The enforcement point 20 is an edge device, such as a cable modem termination system (CMTS), GPRS gateway support node (GGSN), a packet data serving node (PDSN), etc. In general, an enforcement point can be any entity in the network through which packets traverse during the subscriber's session. The enforcement points 20 are not dedicated to any particular application server 12, but instead resources on the enforcement points are allocated to the subscriber's application session by the policy function (e.g., the policy server 18 in this example) in the network.
“Policy function” is used as the generic term for an entity in the network that is performing policy. The primary purpose of the policy function is providing the appropriate Quality of Service for the session, as well as managing any billing and accounting information associated with the session. The policy function is responsible for conveying or “pushing” a policy decision to the enforcement point 20, and making sure the correct set of policies for the subscriber is set. The policy function thus controls the enforcement point 20 via on behalf of the application server 12.
The policy router 16 in the above diagram is a policy function that also can route or forward policy requests to a downstream policy function. In the example of FIG. 1, the application server 12 conveys a policy request to the policy server 20 via the policy router 16.
In general, FIG. 1 shows a service provider policy environment supporting multiple applications, multiple subscribers and multiple subscriber edge devices. The subscriber edge devices 20 function as policy enforcement points for operator policies relating to Quality of Service, Bandwidth Management, and Admission Control.